Change Video Speed
Speed up or slow down videos from 0.25x to 4x instantly. Free, private, and entirely browser-based — your files never leave your device.
Drop files here or browse
Supports MP4, WebM, MOV, AVI — up to 500 MB
Speed change tips
Slow motion
Use 0.25x or 0.5x for dramatic slow-motion effects. Perfect for sports replays, nature footage, or cinematic moments.
Speed up
Use 2x or 4x to create time-lapse or fast-forward effects. Great for tutorials, long processes, or surveillance footage.
Audio preserved
Audio pitch adjusts automatically with the speed change using FFmpeg’s atempo filter. No chipmunk voices or deep rumbles.
All formats
Works with MP4, WebM, MOV, and AVI video files. Output format matches your input automatically.
Privacy first
Everything is processed entirely in your browser using WebAssembly. Your videos are never uploaded to any server.
How to change video speed online
Whether you need slow-motion for a sports replay or a time-lapse of a long process, changing video speed is one of the most useful editing operations. This free tool lets you adjust playback speed from 0.25x (quarter speed) to 4x (quadruple speed) with automatic audio pitch correction.
The tool uses FFmpeg WebAssembly to process your video directly in the browser. Video speed is adjusted using the setpts filter, while audio tempo is corrected using the atempo filter chain. For extreme speeds outside the 0.5–2.0x range, multiple atempo filters are chained automatically to produce natural-sounding audio.
All processing runs entirely in your browser using WebAssembly. Your video files are never uploaded to any server, ensuring complete privacy. The first use requires a one-time download of the FFmpeg engine (~30 MB), after which subsequent operations start immediately.
Frequently asked questions
How do I change video speed?
Drop or select your video file, choose a speed preset (0.25x to 4x), and click ‘Change Speed’. The processed video downloads automatically when complete.
Does the audio change too?
Yes, the audio tempo adjusts to match the new speed using FFmpeg’s atempo filter. The pitch is corrected so voices and music sound natural at the new speed.
What video formats are supported?
MP4, WebM, MOV, and AVI are supported. The output format matches your input file automatically.
What’s the file size limit?
The maximum file size is 500 MB. Larger files may cause browser performance issues since all processing happens locally.
Does changing speed affect quality?
The video is re-encoded at high quality settings. There may be minimal quality difference from re-encoding, but it should be imperceptible for most use cases.